首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2638442篇
  免费   185914篇
  国内免费   7696篇
耳鼻咽喉   34634篇
儿科学   86123篇
妇产科学   72550篇
基础医学   371950篇
口腔科学   71769篇
临床医学   238003篇
内科学   522965篇
皮肤病学   64074篇
神经病学   219364篇
特种医学   101350篇
外国民族医学   738篇
外科学   392107篇
综合类   51165篇
现状与发展   5篇
一般理论   999篇
预防医学   201105篇
眼科学   57450篇
药学   193152篇
  8篇
中国医学   5423篇
肿瘤学   147118篇
  2021年   22868篇
  2019年   22978篇
  2018年   30214篇
  2017年   23619篇
  2016年   26729篇
  2015年   30088篇
  2014年   41159篇
  2013年   61525篇
  2012年   80716篇
  2011年   85087篇
  2010年   51681篇
  2009年   50154篇
  2008年   79636篇
  2007年   84358篇
  2006年   86260篇
  2005年   82349篇
  2004年   79733篇
  2003年   77284篇
  2002年   74407篇
  2001年   129549篇
  2000年   132260篇
  1999年   111596篇
  1998年   32344篇
  1997年   28938篇
  1996年   29177篇
  1995年   28467篇
  1994年   26117篇
  1993年   24219篇
  1992年   85980篇
  1991年   82318篇
  1990年   79500篇
  1989年   76910篇
  1988年   70102篇
  1987年   68710篇
  1986年   64284篇
  1985年   61255篇
  1984年   45665篇
  1983年   38703篇
  1982年   23061篇
  1981年   20626篇
  1979年   39472篇
  1978年   28017篇
  1977年   23853篇
  1976年   22014篇
  1975年   23474篇
  1974年   27275篇
  1973年   25783篇
  1972年   24166篇
  1971年   22294篇
  1970年   20541篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
BackgroundThe aim of this study was to estimate the prevalence of dental prosthetic treatment and to investigate the demographic, social, economic and medical factors associated with the use of fixed and removable dentures in a representative sample of adults living in France.MethodsThe data were obtained from the 2002–2003 Decennial Health Survey, a cross-sectional study of a representative sample of the population living in France, which included 29,679 adults. Information was collected by interview. The variables collected were fixed denture, removable denture, age, gender, number of children, area of residence, nationality, educational attainment, family social status, employment status, annual household income per capita, supplementary insurance, chronic disease, eyesight problems/glasses, hearing problems/hearing aids. Multinomial logistic regression models were used to study the relationship between prosthetic treatment and demographic, socioeconomic and medical characteristics unadjusted, adjusted for age and adjusted for all the characteristics.ResultsThe prevalence of prosthetic treatment was 34.6% (95% confidence interval (CI): [34.1; 35.2]) for fixed prosthetic dentures and 13.8% (95% CI: [13.4; 14.2]) for removable prosthetic dentures. We showed a gradient between educational attainment and removable dentures; the odds ratio adjusted for all the variables (aOR) associated with no or primary education compared to post-secondary education was 2.56; 95% CI: [2.09; 3.13]. When annual household income per capita was low, subjects were less likely to report fixed dentures (aOR = 0.68; 95% CI: [0.62; 0.75]) than those with high annual household income per capita. Individuals without insurance less often reported fixed dentures than those with private insurance. Those reporting chronic disease were less likely to report fixed dentures (aOR = 0.87; 95% CI: [0.79; 0.95]) but more likely to report removable dentures (aOR = 1.29; 95% CI: [1.17; 1.43]) than those without chronic disease.ConclusionThis study reveals social, economic and medical inequalities in fixed and removable prosthetic treatment among adults in France.  相似文献   
3.
4.
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was...  相似文献   
5.
6.

Objectives

Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.

Methods

Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.

Results

A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.

Conclusions

Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight.  相似文献   
7.
8.
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号